摘要:

At frequencies higher than 200–300 cm−1in InP, the classical Drude theory fails to predict the observed wavelength dependence of the absorption coefficient and hence the optical conductivity to which it is proportional. In this paper, the optical conductivity is calculated for InP at 300 °K as a function of frequency and carrier concentration by use of a quantum extension of the Boltzmann transport equation which reduces to the quasiclassical Boltzmann equation in the limit of low frequencies and elastic scattering mechanisms. The conductivity is expressed in terms of a frequency‐dependent relaxation time which reduces to a constant in the far infrared. It is given as a function of carrier concentration over the spectral region from 218 to 2180 cm−1for carrier concentrations from 4.69×1015to 2.13×1018cm−3, and used to calculate the reflectivity spectrum over the same range of frequencies and concentrations. The low‐frequency limit is used to estimate the dc mobility as a function of concentration, and the effect of compensation on mobility is calculated for the purest materials. Comparison with experimental results is given.

ISSN:0021-8979    

DOI:10.1063/1.326722

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Gallium arsenide films have been deposited on graphite substrates by the reaction of gallium, hydrogen chloride, and arsine in a hydrogen flow. The structural and electrical properties of gallium arsenide films have been investigated. The interface between undoped gallium arsenide and graphite exhibits rectifying characteristics; however, a heavily doped interlayer reduces the interface resistance to a tolerable level. MOS‐type solar cells prepared fromn‐GaAs/n+‐GaAs/graphite structures have AM1 efficiencies of higher than 6%.

ISSN:0021-8979    

DOI:10.1063/1.326723

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

New data are presented to show that the transient on‐state characteristics of a chalcogenide threshold‐switching device change significantly when the device is addressed with diagnostic pulses or continuous waves that reduce the voltage beneath the holding level for no longer than 10–20 nsec. In this regime there is no indication of an offset barrier voltage which characterized the blocked on state for longer relaxation intervals. The results suggest the absence of any necessity for a barrier phenomenon and are interpreted in accord with the phase‐transition model for threshold switching rather than the double‐injection theory.

ISSN:0021-8979    

DOI:10.1063/1.326724

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Methods for the fabrication of metal‐insulator‐semiconductor structures with the use of eptaxial PbTe films are described. These methods obviate the need for treating the semiconductor surface. They involve epitaxial film growth in a vacuum environment by hot‐wall epitaxy followed by (1) deposition of ZrO2without breaking vacuum and (2) deposition of pyrolytic SiO2. Capacitance‐voltage characteristics in both cases closely correspond to theoretical values. Depletion‐layer generation is shown to be the dominant contribution to the inversion conductance.

ISSN:0021-8979    

DOI:10.1063/1.326725

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Thin films of essentially single‐phase ErRh4B4have been sputter deposited from an arc‐melted target of ErRh4B4in an ultrahigh‐vacuum system incorporating a liquid‐nitrogen cryogettering can. Optimum conditions for depositing the films were determined. The films exhibit reentrant superconducting transitions withTc’s somewhat different from those reported for bulk material.

ISSN:0021-8979    

DOI:10.1063/1.326726

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The charging and discharging of a dielectric material which has bulk and surface conductivities is discussed. Two model problems are solved. In the first problem, a semi‐infinite dielectric plane, attached to an infinite grounded conducting substrate and exposed to a monoenergetic electron beam, is analyzed. Bulk and surface conductivities and secondary emission characteristics are taken into account as parameters. In the second problem the dielectric is charged but the electron beam is shut off so only the bulk and surface conductivities enter the calculation. The principal result of the latter calculation is to show that steep tangential gradients develop in the presence of a surface conductivity during decay, and that for asymptotic times the temporal behavior, for a fixed position, is proportional tot1/2rather than exponential, as expected in the presence of a bulk conductivity.

ISSN:0021-8979    

DOI:10.1063/1.326727

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A new concept in nonvolatile semiconductor memory using graded or stepped energy band‐gap insulators under the gate electrode of a metal‐insulator‐semiconductor type structure is described. With the graded or stepped insulator, electrons or holes can be injected from the gate electrode at low to moderate applied fields. These carriers then flow under the applied voltage bias into a wide energy band‐gap insulator (such as SiO2) with a purposely introduced charge trapping layer (such as ion‐implanted As, deposited W, or deposited polycrystalline Si). This trapping layer captures and stores electrons (’’write’’ operation) or holes (’’erase’’ operation) with as close to 100% efficiency as possible. Because of the larger energy barriers at the semiconductor (such as Si) interface with the wide energy band‐gap insulator (such as SiO2), few carriers of the opposite sign are injected. Therefore, the substrate Si‐SiO2interface, for instance, can be used strictly for charge sensing (’’read’’ operation) such as in a field‐effect transistor. Several experimental examples are mentioned. A detailed description of stepped insulator structures using thin Si3N4SiO2(≈5.2 eV band gap) layers on (≈9 eV band gap) with an ion‐implanted As region is given. Some advantages of these structures over other nonvolatile semiconductor memory devices are discussed.

ISSN:0021-8979    

DOI:10.1063/1.326728

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The phonon‐assisted laser operation (4.2–77 °K) of multiple quantum‐well AlxGa1−xAs‐GaAs heterostructure diodes is described. Laser operation is observed on phonon sidebands ∼36 meV below the lowest confined‐particle transitions. Tunnel injection into the confined‐particle states, with light emission and negative‐resistance regions, is also observed in these multiple quantum‐well heterostructures. Two different multiple quantum‐well heterostructures grown by metalorganic chemical vapor deposition are described. The first consists of six GaAs quantum wells (Lz∼120 A˚) coupled by five AlxGa1−xAs (x∼0.3) layers (∼120 A˚), and the second is similar except for a reduction in layer size to ∼50 A˚.

ISSN:0021-8979    

DOI:10.1063/1.326729

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Stripe‐geometry multiple quantum‐well AlxGa1−xAs‐GaAs heterostructure laser diodes are described that exhibit tunnel injection with LO phonon participation in the injection and the recombination process. The diodes are constructed by Zn diffusion inton‐type AlxGa1−xAs‐GaAs heterostructures grown by metalorganic chemical vapor deposition (MO‐CVD). At bias voltagesV< (1/q)Eg(AlGaAs) in which tunneling is important, laser operation (4.2–77 °K) of these quantum‐well diodes is obtained an LO phonon energy (∼36 meV) below the first electron–to–heavy‐hole (No. 1 e→hh) confined‐particle transitions of the coupled GaAs quantum wells (six wells,Lz∼120 A˚). In the normal injection bias rangeV∼ (1/q)Eg(AlGaAs), recombination radiation is identified on the No. 2 e→hh transitions and an LO phonon energy below the second electron‐to‐light‐hole (No. 2′ e→lh) confined‐particle transitions. Phonon involvement in the recombination process is identified also in the range between confined‐particle transition 1‐1′ and 2.

ISSN:0021-8979    

DOI:10.1063/1.326730

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The influence of a mechanical modulation of the barrier thickness has been studied theoretically in metal‐insulator‐metal (MIM) point‐contact junctions for different conduction mechanisms: thermoionic, tunnel, and constriction (tiny metallic microbridges) transport currents. Experiments have been carried out between 95 and 300 K on Au‐Al2O3‐Al systems. In the presence of a dc component, the alternating electrical current generated in the junction by the barrier modulation has been phase detected and analyzed with respect to theI‐Vcharacteristic, the junction dynamic resistance, the modulation amplitude, and the temperature. As predicted in the theoretical analysis, the results demonstrate that the tunneling current in the point‐contact junction is very sensitive to the mechanical modulation.

ISSN:0021-8979    

DOI:10.1063/1.326731

出版商:AIP    

年代:1979

数据来源: AIP